Mr O-Ring 172 Viton O-Ring 90A Durometer Pack of 25 - Durable Seal

In this review the Mr O-Ring 172 Viton O-Ring 90A pack is evaluated for technicians, maintenance shops and home mechanics who need reliable chemical and temperature resistance in a common AS568 size. The bottom line: this pack of 25 o-rings delivers consistent dimensions and excellent resistance to fuels, oils and high heat, making it a practical spare-parts purchase for seals exposed to aggressive fluids or elevated temperatures. The reviewer found the 90A durometer balance of firmness and flexibility appropriate for static and low-dynamic sealing tasks where Viton performance matters.

Key Features

• Material: FKM Viton composition provides strong resistance to fuels, mineral oils and many organic solvents, reducing risk of premature swelling or failure.
• Durometer: 90A hardness offers a firm seal that holds shape under compression and performs well at higher temperatures.
• Size accuracy: Actual dimensions are listed and consistent, so fitment for AS568-equivalent grooves is reliable without guesswork.
• Temperature range: Wide operating range from -26C to 232C supports both cold starts and high temperature service environments.
• Pack quantity: Supplied as a pack of 25, which is useful for stocking common replacement parts and reducing downtime.

Who It's For

The Mr O-Ring 172 Viton set is suited to professional mechanics, industrial maintenance teams and hobbyists who regularly service fuel systems, hydraulic components or high-temperature seals and need a resilient material like Viton. Its resistance to gasoline, diesel blends, mineral oils and many chemicals makes it a practical choice where compatibility matters.

It is less appropriate for applications that require very soft, low-durometer seals or for dynamic rotary seals that need specialized compound formulations; users needing extreme cryogenic performance or adhesive bonding should consider other materials.

Pros & Cons

Pros

• Excellent chemical and heat resistance compared with standard elastomers.
• Consistent actual dimensions (8.237 in ID, 8.443 in OD, 0.103 in CS) make installation predictable.
• Pack of 25 reduces repeat ordering and provides spares for routine maintenance.
• Unlimited shelf-life claimed, simplifying long-term inventory management.

Cons

• 90A hardness can be stiff for some low-pressure sealing needs or delicate flange compression surfaces.
• Viton is costlier than general-purpose nitrile for non-aggressive fluid applications.

Specifications

Our Verdict

The Mr O-Ring 172 Viton 90A pack is a sensible buy for professionals and serious DIYers who need durable, chemically resistant seals in an AS568-equivalent size. It offers good value when longevity and resistance to fuels, oils and high heat are required, though customers with very soft-seal needs may prefer a lower durometer option.

Frequently Asked Questions

Are these o-rings compatible with gasoline and diesel?
Yes, Viton is formulated to resist petroleum fuels and diesel blends, including many fuel additives.

Do the listed dimensions match typical AS568 sizing?
Yes, the product notes nominal and actual dimensions that correspond to the AS568 equivalent for consistent fit.

Can these be used for dynamic rotary seals?
They are suitable for many static and low-dynamic applications, but extreme-speed rotary seals may require specialized compounds and designs.